Conventionally, a gas separator is known to use an adsorbent adsorbing or desorbing CO2. For example, Patent Document 1 (Japanese Patent No. 5016179) describes this kind of gas separator. CO2 is an impurity gas that is included in gas used by a battery generating electric power in a battery system, and the gas separator removes the CO2 from the gas. In Patent Document 1, the battery is constituted by a fuel cell. Generally, a fuel cell has an electrode for fuel, an electrode for oxygen, and an electrolyte. Gas including hydrogen (H2) and Oxygen (O2) are introduced to the electrodes. Specifically, H2 is introduced to the electrode for fuel, and O2 is introduced to the electrode for oxygen. When the gas introduced to the electrodes includes CO2, the CO2 comes into the fuel cell and reacts with the electrolyte to form a carbonate. In the result, an electromotive force may decrease due to a decrease of pH, and a surface of the electrodes may be coated by a precipitation of the carbonate. In Patent Document 1, the gas separator removes the CO2 included in the gas (i.e., H2) that is used by the battery generating electric power before the CO2 comes into the battery.
The gas separator has adsorbents that is made of a solid adsorbing agent such as 13× zeolite pellets, and arranged annularly. The gas separator further has a cooler cooling the adsorbents and a heater heating the adsorbents. The cooler and the heater are arranged to be distanced from each other. In the gas separator, an adsorption of CO2 to the adsorbents is facilitated when the adsorbents are cooled by the cooler, and a desorption of CO2 from the adsorbents is facilitated when the adsorbents are heated by the heater. By desorbing CO2 from the adsorbents, the adsorbents return to a condition to adsorb CO2 easily. In the following description, an area in which the adsorption of CO2 to the adsorbents is facilitated by the cooler will be referred to as an adsorption facilitating area, and an area in which the desorption of CO2 from the adsorbents is facilitated by the heater will be referred to as a desorption facilitating area.
In the gas separator, the adsorbents arranged annularly are rotate clockwise such that the adsorbents in the adsorption facilitating area and the adsorbents in the desorption facilitating area are switched in turn. Accordingly, in the gas separator, the adsorbents come into the adsorption facilitating area one after another, and CO2 can be adsorbed continuously without waiting the adsorbents of which CO2 adsorption capacity is full to return to the condition to adsorb CO2 easily. On the other hand, when a single adsorbent is used, and when the adsorbent is not ready to adsorb CO2, the battery cannot generate electric power. In contrast, according to the gas separator of Patent Document 1, the battery can generate electric power continuously as the CO2 is adsorbed. As described above, the gas separator of Patent Document 1 removes CO2 from the gas that is used by the battery generating electric power in the battery system.
However, according to studies conducted by the inventors of the present disclosure, in the gas separator of the Patent Document 1, a component such as a pipe is required for each of the adsorbents made of a solid adsorbing agent. Moreover, a device to rotate components such as the adsorbents and pipes is required. Thus, there is a possibility that a complicated mechanism may be needed, or the gas separator may be upsized as a whole.